Methods of making wall plates and the like



Nov. 21, 1944. A, BRUND METHODS OF MAKING WALL PLATES AND THE LIKE Filed Dec. 21, 1945 J mh A. Brund Patented Nov. 21, 1944 UNITED" STATES PATENT OFFICE "This invention relates 'to the manufacture (of flame protective tiles, mall panelling iplates,

wall lining' plates, 'tinsulating plates, wall decorating and ceiling iplateanncornices, :pieces of sculpture, wall finishing coats, ceiling coats and various other articles and structures that are made, wholly or in part, f a plaster or mortar hardening-on drying. More particularly theinvention relates to the manufacture of such J articles or structures when made, wholly or inppart, of a plaster or mortar containinga substance,

such as :quicklime, or hydrated limepmagnesia or' the like/that is capable of chemical reaction with carbon dioxide, or carbonic acid, to form a c'arbonate practically insoluble in water.

"One' bjct of the invention :is t'o provide a method "for using lime plaster -'or mortar '--w ith suecess'for the'manufacture =o'f such articlesand structure as are otherwise usuallyniadeof gypsum plaster. That lime plaster or mortar could hitherto not be=used with 1 success for the manuf acture of 'the' articles and structures in-' question,

was substantially-due to the fact that lime plaster or mortar*-would taketoo long a *time to set orharden and' would not attainth'e necessary; undesirable,strength. l A further object 'of"the invention is-to wovme a'method for obtaininga relatively*quick hardening and a relativelyhigh strength of :lime and like "plasters and mortars "when used in, or for; the manufacture of articles and structures-of such variouskinds as fhereinbefore referred to by way of example.

The. above and other objects of the invention ,Will' become apparent from the (following, v description and .the accompanying drawing in which- Fig. '1. is -a iagram illustrating the relation between porous volumeand water content of a lime plaster or mortar.

.liig. 2 is la diagrammatic sectional view ofta.

carbonic acid hardening chamber for carrying out the method of. the invention according .to

oneiorm thereof.

out the .method of .the invention according to 1 a second-form thereof.

fig. 4 is "a sectional view of awwall orceiling coat of lime plaster, .and illustrates; a .form .of the invention :for icarbonic acid hardeningkot suchsa mcoat.

:i lig. 5 Jis :sa .:sectional view ;of ca pillar :having ra coat-Inf rplaster, .:and :illustrates :a :zformrtof the invention for carbonic acid: hardenin of i said coat.

Figs. .6 to illustrate, by way of example, various (articles -.or structures. that can. prefer.-

ably be made, wholly or in part, of .lime. or..1ike

plaster :or .mortar when carbonic acid hardening the .latten-according to. the method of this in.-

vention, Fig. :6 isa perspective 'view of ,a Lflame protective "tile, v Figs. 37,8, .9,,10-and 11 q-aresec 1o tional-views of-different fiormstof ;insulating or wall panelling, plates shaving-ion ;one side or both sidesra flame protective coat of .lime or tlike plastertorlmortar. I 7 plate shown in Fig. ii. a Fig. wisatper tive 15; view -of gaqcornice. :14. isa sectional .view of a decorating .or ceiling plate.

Eig. :12. is ;a plan viewvof .the

Fig. 15 istan elevation of a piece of sculpture.

It is we1ll known -thatrthe;setting.. or hardening :of :lime' plastevsl and mo'rta rs .in the. air is:

caused, to =arcertain. degre.e:at;least,;by the 1f orina tioniof; calcium carbonatein the plaster. or. montar tby chemical reaction of the calcium ,h y drate ttherein. with carbonic (acid having sits origin intthe carbon dioxide ,inwtheq-ait. This chemical; reaction, however,.-is:but slow .on raccountl of "the; small carbon dioxide content of-the air.) ,Tmexpedite the-reaction ithas doeen -pto posed -.to produce; and ;;maintain an atmosphere of :a l'higher carbon dioxide -.content in ".the sur- 3 .roundings; of the .plaster or :mortar during the setting mrrhardening thereof. But evendf'the hardening process ,could be expedited :to .a cere taindegreeiin this may, it zstillrrequiredta considerableulength -01. rtime rand, furthermore, .-no lap- .preciable .iincrease; but -:of-ten :a' decrease, of the resulting 1. strength :of tithe plasteryor mortar was obtained-imthisway. i i

.The 1' lack -.hitherto 201:- a :quick method :for scar-- boniczsacid :hardening I'Df lime plaster :and amor- 40 1tar to axhig'h'degreecofistrengthgisrobvio s yudlte to :thecfact ithat those skilled lin :the tart 1113113110 exact knowledge 1101-; the chemical and physical conditionstof the rprocess 1 causing :the hardening. It might betmentioned by a -wayzof :example Ethat carbonic acid hardening chamber for ,carrying process :was: not known... ;':In: certain! technical Eliteratureitthasreven beenustated that aggenerally valid tlime=water ,ratio i(kg. *water ;:per :kg'. ,lime) cannot :berasceitained precisely. 1.01115 little -.was

1 .,knownaof the cheat 10f surplus water, or :water formed during; the rreaction, or of the, elimination :of such v waterrin ith'e. course of ,ithezprocess.

Towsolve theseiproblems itSis-necessary lto give upath 101d ,nidearthat lime; in zatplaster; or t mortar :can without :further. ado give a crystallized zeal.-

carbonate may take place by exchange of ions,

according to the following formula:

Ca" +'2OH +2H' +CO3 =CaCO3+2HzO The necessary, or optimal, quantity of water for the reaction is not to be seen from the quantitative equation of this formula. The necessary, or

optimal, quantity of water for the reaction must therefore be ascertained in another way, for which the following rules may serve as a guide. As indicated in the'diagram in Fig; 1 of the drawing, with an increasing addition of water to the mortar the porous volume thereof increases from an original value a to a maximum value b and thereafter decreases again to a value (1 at which value, when the mortar is packed to the desired degree, water begins to trickle outthrough the surface of the mortar. Generally the value it is considerably lower than the value a. The greater the porous volume is, the smaller the contact between the particles in the mortar is. If the quantity of water is less than that corresponding to the value b, the formation of carbonate crystals is but weak, the crystals thus formed not being able to grow or develop to a substantial size or come into substantial contact with one another, partly on account of the quantity of Water being rather small, partly on account'of the contact between the particles; which favours the crystallization, at the same time being relatively small. If, on the other hand, the quantity of water is greater than that corresponding tothe value (1, part of the added water will ooze out through the surface of the -mortar. This surplus water contains lime, and as long as this water has not evaporated, it retards the crystallization because it obstructs the water in the mortar, including that water arising from the reaction, from escaping to the surface and'evaporating. As the crystallization conditions thus also become lessfavourable, if the quantity of water exceeds that value corresponding to d, the quantity of water should obviously be such as corresponds to a value lying between I) and d.

/ But as a substantial contact between the par-7 ticles in the mortar is favourable for the crystallization, such contact ought to be as great as possible without entailing the risk of water trickling out through the surface of the mortar. Hence the optimal quantity of water ought to be such as to correspond to a value which like that shown by way of example in Fig. 1 and designat-- ed with c, is in the neighbourhood of the value d.

closes the water in the interior of the mortar.

7 atmosphere, As the atmosphere containing, and

preferably rich in, carbon dioxide is maintained in a moisture charged condition, little or no evaporation of water takes place on that side or surface of the mortar exposed to this atmosphere and, therefore, in spite of the carbon dioxide content of this; atmosphere being relatively high, no crust is formed on the surface of the mortar exposed to this atmosphere, and so the continued penetration, or absorption,of carbon dioxide into the mortar and solution in the water contained i therein will not be obstructed. The carbon dis; oxide dissolving in the water in the mortar dif-- fuses through the latter towards the evaporating 1 side, and because the evaporation of the water" from the mortar on this side thereof does not interfere with the penetration, or absorption, of

carbon dioxide into the mortar through the other side thereof, the evaporation of the water from the mortar on the evaporating side may be regulated in such a way that a complete conversion ofthe lime content in the mortar to awell crystallized calcium carbonate of limespar type is secured, with the result that the mortar attains an unusually high strength. In this way the hardening of lime plaster or mortar in any thick nesses usual, or desirable, in such various articles and structures as herein referred to, can

be carried out in a sufficiently short time and with the aid of sufficiently simple means to make the herein described. method of production advantageous both technically and economically.

So that the invention maybe clearly understood some simple forms of means for carrying it into effect are illustrated:m ore or less diagrammatically in Figs.. 2 to 5 on the drawing.

According to the form shown in Fig. 2 the carbonic acid hardeningprocess is carried out'ina chamber I provided with. a horizontal partition 2 dividing the chamber into a lower comparttures 5 and supports moulds 6 having bottomsl that are foraminous or otherwise'permeable to carbon dioxide and, for instance, consist of wire or screening, perforated sheet'metal, fibrous ma: The moulds 6 are placed" with their permeable bottoms "I over the aper-. tures 5 in the partition 2. of the lower space 3 serves as a water container.

terial, cloth or the like.

The bottom portion Supply conduits. 8 for carbon dioxide or gases containing, and preferablyrich in, carbon dioxide, e. g., combustion gases, debouchunder When purecarbon" the surface of the water 9. dioxide is supplied, it may be taken from a high pressure container therefor through'a pressure reducing valve, and when combustion gases or the like are supplied, they may be propagated by means of a fan or the like. The upper space 4 is adapted to be ventilatedin a suitable Way; l by means of fans It for fanning air through it, for example, the air being heated orits relative humidity regulated, as required,. in any other suitable manner. Lime plaster or mortar whose.-

messa e.

which it remains: during thehardening, the b'otwater content has been suitably adjusted in ac cordancew-ith-the invention, is cast, or otherwise 1 placed and shaped as desired, in the moulds I 6 and 1 allowed to remain in I these moulds during the hardening process. In carrying out this process a moist atmosphere containingand preferably rich in, carbon dioxide is produced and maintained in the space 3 by introducing car-:

bon dioxide, or gases containing'carbon dioxide,

into this space throughthe water 9, so that the carbon dioxide or gases bubble up through the water and thus become charged with moisture.

Water is evaporated from that surface of. the

tom"ofnthe mould may by way of e p wk sist'of a' 'fibrousboard or sheet which during the settingxor hardeningofthe mortar adheres or mortar facing space 4, and the evaporation is regulated in a manner suitable for thehardening process by means of regulating the ventilation of this space. through which ventilation the evaporated water is eliminated. During the hard ening processpreferably a certain, though small,

difference in pressure is maintained between the atmospheres in the spaces on either side of the binds to the latter. When usingmoulds of the kind showtn invFig. 2,19. fibrous plate or sheet maybelaid on the bottom I of the mould before filling thelimeplastercormortar. into the mould.

When. applyingxthe lime plaster orrmortar in a continuouslayer onto asupport running through the hardening chambergthisysupport may 0011-.

sistrof fibrous material; When using an endlessnonveyer as shown in Fig. 3,. a fibrous plate orwzsheet l4 maybe continuously introduced between the endlessficonveyer Hand the limemortar 13 in applying the .latter onto the conveyor...

It isvalso :possible to provide a fibrous plate or diaphragm formed by the mortar, and in such .a way that the pressure of the moisture charged atmosphere rich in carbon dioxide is predominant. 1 This difference in pressure promotes the penetration, or absorption, of the carbon diox- 1 ide into the lime mortar and to the passing of the carbonic acid and moisture through the lime mortar rom the carbon dioxide supply side towards the water evaporating side. I

According to the illustrative form of the invention justdescribed the hardening process is carried out discontinuously, which may be prefarable, whenit is a question of the hardening of a piece of sculpture or like articlesof more org less irregular .shapeand size and moulded in lime plaster or mortar. In the case of mass production of flame protectiveor panelling plates or tiles and theflike of regular form and size it is preferable to carry out the production, includused for the casting of the plates and having I bottoms permeable to the carbon: dioxide may be I provided, or placed, on an endless conveyer running through the hardening chamber. r I As illustrated in Fig. 3 the permeablev support for the lime plaster or mortar during the hardening may. also consist of an endless. permeable conveyer ,1! running through the hardening chamber l, the lime plaster or mortar being applied, e. g., pressedjout through a nozzle, I2, in the formof a layer l3 onto this conveyer before, or on, entering the hardening chamber. In this way a continuous lime plate may be produced which is continuously removed from the supporting conveyer on, or after, its exit from thehardening chamber. This continuous plate, may afterwards be divided into pieces of any desiredsize,

but such division can of course also. beperformed before the hardening, if desired. li he conveyerl2] may consist of metal Wire netting (like a paper machine net) or of fine metalnetting or of. cloth. 1 I i As a lime mortar support: permeable to the, carbon dioxide during the hardening process,

it; is also possible to use a layer, for instance in,

th form of a. plate. or sheet, oi fibrous material I of such a-n'ature that the lime mortar during;

the setting or hardening adheres to, this fibrous layer. When. castinglime'mortar mamould sheet, for instancesas shown at I5 in Fig. 3,. on

the upperside of,. and in such contact with.

the lime mortar to be set or hardened that the mortar-whilst setting or hardening adheres or binds to this :plate or sheet, through which, when itis *on the evaporating side of the mortar, the elimination or; evaporation of the water from the mortar during the hardening takes place. Thus composite panelling plates'orthe like of hardened limemortarhaving a reinforcing: or

insulating; layer or the like of fibroustmaterialr on' onewside or both sides may be produced.

' Plates, panels or the like may of course be manufactured with an inner reinforcement of any nature, or with an inner insulating layer of fibrous or porous nature. In order to strengthen the adherence or bond obtained between the 1 fibrous material and the lime or like plaster or mortar during the hardening of the latter, the fibrous'material may be soaked with lime milk or, the like before bringing it in contact with the plaster or mortar to be hardened. This method of strengthening the adherence or bond is generally applicable to the production of composite articles or structures ofa fibrous material and a plaster or mortar comprising a binding. agent, such as burnt lime or slaked lime,

{hardening under the influence of carbon dioxide. In all such cases the fibrous material may be soaked with a solution, or suspension, of such binding agent and then be. allowed to dry more ;or less before the fibrous material and the plaster or mortar are brought :into contact with one another to form. the desiredarticle or structure;

which is thensubjected to the herein described hardenin process. If and when drying the soaked fibrous materialfbefore the application. of the plaster or mortar thereto, care should be takento avoid the formation of a crust. on the surface of the soaked fibrous material. The binding agent absorbed by the fibrous material will form roots therein, so to say, which during the hardening. process bind to the plaster or mortar in contact with the fibrous material. Figs. .6 to 15 show various panelling, and insulating plates and other articles that can preferably be manufactured in accordance with. the method of this invention, and in these figures the reference numeral l1 denotes hardened lime or like plaster or mortar, whilst the reference numeral I8 denotes fibrous or like porous mate- I rial.

The support carrying the plaster or mortar maintained during the hardening, may consist ofnan interior hollow space in the reinforcement or revetment which, for the purposes in question,'may consist of a revetment mator the like of thin pipes into which the moist carbon dioxide atmosphere is introduced, said pipes being perforated for permitting the passage of the carbon dioxide to the'mortar. By means of such a modification of the'method it may be used even for hardening a finishing layer of lime plaster or mortar on a wall, ceiling or the like. As illustrated in Fig. 4 a mat or thelike of thin revetment pipes l9 isflxed to a wall 20 forholding a coat 2| of lime plaster or mortar, the pipes being providedwith the perforations on that side facing the wallso. that a choking. of the holes is. prevented when the lime plaster or mortar isapplied. .Theregulated evaporation of water from the lime plaster or mortar during the hardening process takes place on the outer surface of the coat 2l by means of fanning and heating of the air there. To facilitate this fanning and heating, or for making same more effective, a limited space 22 may be provided adjacent the surface of the lime mortar by erecting a.provisional wall 23 of tarpaulin, wood fibre plates or the like at a suitable distance from the said surface.

According to the form of the invention illustrated in Fig. 5, a pillar or the like is made by providing a perforated metal tube'24 with an outer layer 25 of fibrous material, and with a coat 26 of lime plaster or mortar on said fibrous material, the said'coat being hardened by. introducingmoistgases rich in carbon dioxide into the tube zli whilst evaporating water from the outer side of the coat by fanning air, heated as 1 requested, through a space '21 formed between the coat 26 and a provisional wall 28.

It is to be understood that theterm plaster or mortar used hereinbefore and-'in the appended What I claim and desireto secure by Letters Patent. is:

1. In the manufacture of wall plates, wall coats and other articles and structures that are made,

wholly or in part, of a plaster or mortar hardenoration of water from the plaster or-mortar on that side thereof subjected to this last-mentioned atmosphere 2. In the manufacture of wall plates, wall coats and other articles. and structures that are made, wholly or in part, of a plaster or mortar hardening on drying, the herein described method which comprises using 'a lime plaster or mortar, and hardening said plaster or mortar by maintaining on different sides thereof a moist atmosphere containing carbon dioxide, and an atmosphere of sufficiently low relative humidity to cause evaporation of water from that side of the plaster or mortar exposed to this last-men-- tioned atmosphere.

3; In thernanufacture of wall plates, wall coats and. other articles and structures that are made, wholly or, in partgof a plaster or mortar hardening on drying, the herein described method which comprises, using a plaster or mortar hardening under the influence of carbon dioxide, moulding said plaster. or mortar, maintaining in separate spaces a moist atmosphere containing carbon dioxide and an atmosphere of a relatively low.- relative humidity, and hardening the moulded plaster or, mortar by letting same form a diaphragmbetween said spaces. r

. 4. In the manufacture of wall plates, wall coats and other articles and structures, the herein de scribed method which comprises moulding a plaster'or mortar hardening under the influence of carbon dioxide, causing the moulded plaster or mortar to form a diaphragm between two spaces, charging one of said spaces with a moist atmosphere containing carbon dioxide, bringing about an atmosphere of such reduced humidity in the other space as tocause'an evaporation of Water from the surface of the diaphragm exposed to this last-mentioned atmosphere, and maintaining these diiferent atmospheric conditions in the spaces on opposite surfaces of the intermediate diaphragm until the plaster or mortar has set and hardened. I i l 5L The method of producing articles and structures ofa plaster or mortar hardening under'the influence of carbon dioxide, which comprises shaping the plaster or mortar into a desired form and, in'so doing, arranging it as a diaphragm between two. spaces, passing carbon dioxide to one of said spaces, charging the carbon dioxide with moisture during the passage thereof to the said'spaceybringing about an atmosphere of-such reducedhumidity in the other of said spaces as to cause an evaporation of water from the sur faceiof the diaphragm facing this last-mentioned space, and maintaining said different atmospheres in the spaces on opposite surfaces of the intermediate diaphragm until the plaster or mor tar has set and hardened.

61 The method of producing articles'and structures of a plaster'or mortar hardening under the j influence of "carbon dioxide,'which comprises shaping the plasterer mortar into a desired form. letting the shaped plaster or mortar form a diaphragm between separate spaces, introducing moist gases containing carbon dioxide into one of said spaces,and ventilating ,air of such -re-' duced humidity through the other of said spaces as'to cause an evaporation of water from the surface of'the' diaphragm facing this last-men tioned space. 1 I

'7. The method of producing articles and structures of'a plaster or mortar'hardening under the influence of carbon dioxide, which comprises shapin the plaster or mortar into a desired form and then hardening it by letting it act as a .diaphragm between two spaces and by mainpressure being maintained in the first-mentioned than in the last-mentioned of said spaces,

8. The herein described method which comprises moulding an article or structure of a plaster or mortar hardening under the influence of carbon dioxide and then hardening it by subjecting it on one of its sides to heated drying air, while simultaneously supplying carbon dioxide in a l moist state to another side of the article or structure.

9. The herein described method which com- 1 prises moulding an article of a plaster or mortar hardening under the influence of carbon dioxide, by depositing the plaster or mortar into a mould with a bottom permeable to carbon dioxide, ar-

ranging the mould containing the deposited plaster or mortar in such a manner thatthe plaster or mortar forms a diaphragm between two spaces,

charging one of said spaces with moist carbon dioxide, and ventilating the other of said spaces for evaporating water from the plaster or mortar in the last saidspace. l l l l l 11. The herein described method which comi i 5 on both sides with a plaster or mortar hardening under the influence of carbon dioxide, and then hardening the plaster or mortar by subjecting the coated plate or sheet on one side to a outer surface of the said coat.

moist atmosphere rich in carbon dioxide, while simultaneously evaporating water from the other,

side of the coated plate or sheet.

15. The herein described method which comprises applying a plaster or mortar hardening under the influence of carbon dioxide as a coat to a revetment made of thin perforated hollow members erected in the roximity of a wall or ceiling, introducing a moist gaseous medium comprising carbon dioxide into said hollow members, and heating and circulating the air adjacent 16., The herein described method which comprises providing a wall or the like with a revetment of hollow unilaterally foraminated members with their foramina facing the wall, apply ing a coat ofa plaster or mortar hardening under the influence of carbon dioxide onto said revet- Y ment, and supplying a moist gaseous medium comprising carbon dioxide tosaid coat through prises depositing a layer of a plaster or. mortar hardening under the influence of carbon dioxide on a foraminous endless band continuously running through a chamber and dividing said chamber into two spaces, charging one of said spaces.

with a moist atmosphere containing carbon dioxide, and ventilating the other of said spaces for evaporating water from the surface of the mortar in the last said space.

i 12. The method of producing a a composite article orstructure of a fibrous material and a plaster ormortar hardening under the influence of carbon dioxide, which comprises depositing a layer of such plaster or mortar associated with a fibrous material onto aforaminous endless conand dividing said chamber into two spaces,

; charging one of saidspaces with a moist atmos- .phere containing carbon dioxide, ventilating the other of said spaces 'for evaporating water from the plaster or mortar, and discharging the said plaster or mortar and associated fibrous material from said conveyer.

13. The herein described method which comprises coatinga permeable fibrous board or sheet on one side with plaster or mortar hardening under theinfluence of carbon dioxide, and then hardening the plaster or mortar by subjecting the coated board or sheet on one side to a moist atmosphere containing carbon dioxide, while outer surface thereof.

said hollowforaminated members, whilst drying said coat through evaporation of water from the 17 The method as; claimed in claim 16, which comprises erecting a provisional wall at a short distance in front of the applied coat, and circulating heated air through the space between the coat and the said provisional wall to promote,

and to afiord an opportunity to regulate, the

evaporation of water from theouter surface of the coat.

1s. The method-claimed in claim 1, in which the, plaster or mortar tobe used is given a water content approaching that at which water begins veyer continuously running through a chamber to trickle out through the surface of the plaster or mortar when packing same to the desired degree.

19. The method of producing a composite article or structure of a fibrous material and a plas-' ter or mortar comprising a, binding agent hardening under the influence of carbon dioxide,

which comprises soaking the fibrous material with a solution of such a binding agent, then applying, said plaster or mortar and said soaked fibrous material in contact with (one another for forming the desired composite article or structureQand finally hardening said plaster or mortar, while in contact with said fibrous material,

by subjecting the articl or structure formed on simultaneously evaporating water from the other side of the coated board or sheet.

14. The herein described method which comprises coating a permeable fibrous plate or sheet one side to a moist gaseous medium containing carbon dioxide, and on another side to a gaseous medium of relatively lowrelative humidity for evaporatingwater from the article or structure on last said side thereof.

JOHAN ALB RT BRUND.

the 

